The Oașa Dam is a reservoir on the Sebeș River, located on the border of Alba and Sibiu counties, in the Șureanu Mountains, at an altitude of 1255 m. With an area of 441 ha and a volume of 136 million m³ of water, it is the largest lake accumulation on the Sebeș river.
The dam, located in the Oașei Gorge, was completed in 1979 and is built of anchorage with a reinforced concrete mask. It has a height of 91 m, a maximum width at the base of 250 m and a maximum length of 300 m. The resulting Lake Oașa has a useful volume of 136 million m³, an area of 460 ha and a length of approximately 6 km. The Ciban River was impounded to increase the flow. The type of dam was chosen due to the presence of a high percentage of mica in the ballast in the area, unsuitable for the concrete required for an arched dam.
In 1980, the Gâlceag underground power plant was put into operation, which uses the energy potential of Lake Oașa. The cavern-type Gâlceag hydroelectric plant has a main gallery of 8.2 km and is equipped with two Francis groups of 75 MW each. Also, the Gâlceag pumping station, with two hydropumps of 10 MW each, brings additional water from the Cugirul Mare river. In the future, the Canciu lake will also be fed by the waters of the Cugirul Mic river through an underground tunnel of 3400 m.
The main tributaries of the Valea Frumoasei river (the name of the Sebeș river until it flows into the lake) are Tărtăru, Curpătu, Sălănele, Smida and Valea Mare.
The predominant fish in the lake are trout and crayfish. The dam is crossed by the DN67C (Transalpina), which connects the cities of Sebeș and Novaci.
//
The Oașa reservoir is located in the commune of Șugag, Alba county, on the upper course of the Sebeș River, at an altitude of 1,255 meters, after its confluence with the Bistra River, being positioned between the slopes of the Șureanu Mountains (to the east) and those of the Cindrel Mountains (to the west), and having as landmarks the Oașa Mare peak (1,731 meters) in the Cindrel Mountains and the Fetița peak (1,690 meters) in the Șureanu Mountains.
Built between 1974 and 1983, the dam is made of rockfill with a reinforced concrete mask, having a height of 91 meters, a length of 300 meters, a width of 250 meters at the base and only 10 meters at the top; the Transalpina highway passes over this dam, connecting the city of Novaci in Oltenia with the municipality of Sebeș in Transylvania.
The reservoir that formed behind the dam is approximately 6 kilometers long, with a variable width, an area of 460 hectares and can hold a volume of 136 million cubic meters; its banks are completely covered by dense coniferous forests, dominated by spruce and fir.
The water of Lake Oașa feeds the turbines of the Gâlceag hydroelectric power plant, which became operational in 1983, being equipped with two energy units of 75 MW each, totaling an installed capacity of 150 MW.
Sursa: romaniadategeografice.net
